Some humans experience sensitivities or allergic reactions to airborne micro-particles. Such particles may be feline-spawned allergens such as cat dander. Other particles may be, for example, dust mites or the feces or exoskeleton of dust mites. Dust mites are of particular concern due to their propensity to propagate in cushioning materials such as mattresses, pillows and furniture cushions.
Dust mites are arachnids, and belong to the subclass acari. There are two common dust mites: the American house dust mite (Dermatophagoides farinae) and the European house dust mite (D. pteronyssinus). Dust mites feed on the dead skin that falls off the bodies of humans and animals and on other organic material found where they live. They are extremely small, being only about 100-1000μ. Moreover, dust mites are virtually transparent and can be difficult to see without sophisticated microscopy. Dust mite feces and exoskeletal particles are even smaller, and can be 10 to 20 microns.
It is now generally accepted that dust mites, dust mite feces and other microscopic allergens are a significant cause of many asthmatic and allergic reactions in the home. Such micro-particles may be inhaled by a human coming into contact with infested pillows or bedding. To reduce exposure to dust mite allergens, various suggestions have been made for covering bedding in covers which act as a barrier to the passage of allergens. In this respect, it is known to cover allergen-bearing articles such as mattresses and cushions with a cover which serves as a dust-mite barrier. Such coverings define plastic materials or finely woven materials having openings of a size sufficiently small to inhibit the passage of dust mites there through. For instance, U.S. Pat. No. 5,050,256 discloses an allergen-barrier bedding cover made from a coated fabric. The fabric is said to have a pore size of less than 10 microns to prevent the passage of dust mites. The fabric is sewn to form the cover and the seams are sealed with an additional coating of polyurethane.
U.S. Pat. No. 5,321,861 discloses a protective cover for upholstered or padded articles. The cover is made from a microporous ultrafilter material having pores of less than 0.5 microns. To eliminate possible leakage of allergens through the seams or zipper closure, the cover is constructed using high frequency welding, and the zipper is covered by an adhesive tape.
U.S. Pat. No. 6,017,601 entitled Allergen-Barrier Cover presents a cover fabricated from a multi-layered fabric material. The material defines meltblown and spunbonded layers made from polypropylene which permits the passage of air but is said to be impermeable to the passage of water and of dust mites.
It is noted that the solutions offered from the above patents primarily attempt to trap dust mites within an allergen-carrying article, but do not seek to eliminate them. Further, the solutions do not enhance the cushioning or comfort of the user on the allergen-carrying article as would be offered by a nonwoven-based article.
Conventional miticides (or acaricides) based upon organophosphate compounds have been used for the extermination of mites. Such compounds are typically diluted in an aqueous spray. However, such compounds, while effective in eradicating mite infestations outdoors such as in farms, are not feasible for indoor use. In this respect, such acaricides are toxic to humans, and the extermination of mites by spraying of miticide chemicals has the side-effect of polluting the inhabited environment while also posing a toxicity risk for humans, particularly children and infants, as well as cats. Further, organophosphate acaricides cannot be used on beddings and, therefore the mites are left undisturbed in their main living site.
It is proposed here to provide a nonwoven structure having a tacky characteristic as a trap or filtering medium for allergens. In addition, a method for trapping allergens using a tacky material around an allergen carrying article is provided. Also provided herein is a “tacky material” defining a substrate which receives a tacky adhesive for trapping micro-sized particles such as dust mites.